Comparison Between Manual Calculation and Software Calculation of G+5 Building using STAAD

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Comparison between Manual calculation and Software calculation of

G+5 Building Using Staad pro

M.A. Qureshi

1,

_{Nidhi Bhavsar}

2

_{, Pratiksha Chaudhari}

3

_{, Parth Panchal}

4

_,

Siddharth Mistry

5

_{, Ankit Makadia}

6

1

Assistant Professor, Civil Engineering Department, FETR, Bardoli, Gujarat, India

2,3,4,5,6

_{Students, Civil Engineering Department, FETR, Bardoli, Gujarat, India}

---*---Abstract -**

Earthquakes are known to produce one of the most destructive forces on earth. It has been seen that during past earthquakes many of the building were collapsed. Therefore, realistic method for analysis and design are required. Performance Based Design is the modern approach for earthquake resistant design. It is an attempt to predict the performance of buildings under expected seismic event. In this present study a G+5 multi-storeyed hospital building is analysed by seismic action situated at different zone. It involves the calculation of load and total Seismic weight of building from that the base shear is calculated in different zone.

Key Words: Analysis and comparison, Earthquake

Behaviour, STAAD Pro, Base Shear

1. INTRODUCTION

Buildings constitute a part of the definition of civilizations, a way of life advanced by the people. The construction of buildings should be looked upon as a process responded to human requirements rather than as a product to be designed and built a great expense.

It is well known fact that users of any software for structural analysis and Design do not know whether the program is having any bugs or its correctness while using. Since any program developed may contain some error or bugs it is necessary for the users to check the model and analysis and design results manually.

Base shear is an estimate of the maximum expected lateral force that will occur due to seismic ground motion at the base of a structure.

Earthquake-resistant structures are structures designed to withstand earthquakes. While no structure can be entirely immune to damage from earthquakes, the goal of earthquake-resistant construction is to erect structures that fare better during seismic activity than their conventional counterparts.The main objectives of earthquake engineering are:

 Forces the potential consequences of strong earthquakes on urban areas and civil infrastructure.

 Design, construct and maintain structures to perform at earthquake exposure up to the expectations and in compliance with building codes

1.1 Objective

 To compare the results of base shear by manual analysis and Staad

 The input data while modelling the structures is correct.

 The assumed and the input loads on the structure are in par with the actual condition of the structure.

 The support condition considered are as per site condition.

1.2 Features of Staad pro

 Quality Assurance

 Broad Collection of design codes

 Covers all aspects of structural engineering

 Reports and Documentation

2. Methodology

Determination of design earthquake forces is computed by the following methods:

1. Equivalent static lateral method 2. Dynamic Analysis

In the first method, different partial safety factors are applied to dead, live, wind earthquake forces to arrive at the design ultimate load. In the IS: 456-2000 code, while considering earthquake effects, wind loads assuming that both severe wind and earthquake do not act simultaneously. The American and Australian code recommendations are similar but with different partial safety factors

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3. Load Calculation

Fig -1: AutoCAD Plan

I. Dead load

a) Floor Load

Slab Load

Self-weight of slab = 3.75 kN/m²

Floor finish = 1.5 kN/m²

Total Load = 5.25 kN/m²

Terrace Load

Self-weight of slab = 3.75 kN/m²

Floor finish + Water proofing = 1.5 kN/m²

Total Load = 6.95 kN/m²

b) Wall Load

External Wall of 230mm thick

Floor height = 4000 mm

Beam depth = 0.75 m

Total Load

[2 (4 – 0.75 – 0.75)6 + 2(4 – 0.15- 0.15)4] ×0.23 × 20

= 274.16 kN/m

Internal Wall of 115mm thick

Floor height = 4000 mm

Beam depth = 0.75 m

Total Load

[2 (4 – 0.75 – 0.75)6 + 2(4 – 0.15- 0.15)4] ×0.115 × 20 = 273.70 kN/m

c) Beam Load

Longitudinal beam

Self-weight of beam = 25*.75*.3

Total load

(6 × 5) × (4 – 0.75 -0.75) ×5.63 = 422.25 kN/m

Transverse Beam

Self-weight of beam = 25*.75*.3

Total load

(4×7) × (4 – 0.75 -0.75) ×5.63 = 583.27 kN/m

d) Column Load

Self-weight of Column = 25*.75*.75*35

Total Load = 492.18 kN/m

e) Parapet wall

Total load

= (24×2 + 16×2)

×0.115×20

= 184 KN

II. Live Load

Load on floor =24 × 16 × 0.5 ×4

= 768 KN

 Weight of floor

[2016 + 422.25 +

583.27+2×445.51+2×444.76+2×984.36]+768

=7537.85 KN

 Weight of roof

[2668.80 + 422.25 + 583.27 + 184 ×1 + 274.16 ( )

+ 273.70 ( ) + 492.18 × ] + 0

=5732.05 KN

 Total Seismic weight of building

= Weight of roof + 4*Weight of floor

=

5732.05 + 4 × 7537.85

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[image:3.595.51.556.72.780.2]

Table-1: Base shear results (manual)

4. Building Modeling in Staad pro

Fig-2: Staad Plan of G+5 Building

Fig-3: G+5 Building

Fig-4: Assign Properties of Concrete Members

Fig-5: Assigning Loading

Fig-6: Magnitude of load

Fig-7: Generation of seismic zone

Zone ₂ ₃ ₄ ₅

ZONE FACTOR _0.10 _0.16 _0.24 _0.36

I _1.5

R ₅

SOIL TYPE _Soft

h (m) ₂₀

W

(KN) 35883.45

Ta in (X) =0.075(h*0.75) (sec)

0.709

Sa/ g

=1.67/T 2.36

Ah =(ZI/2R)

(Sa/ g) 0.035 0.05₇ 0.084 0.127 Vb (X) = W

[image:3.595.304.562.93.228.2]

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[image:4.595.142.552.82.436.2]

Fig-8: Load Assigning

Fig-9: Performance of Analysis

4.1 Base shear by Staad pro

Table-2: Base shear by Staad pro

5. Comparison between results of Base shear

Table-3: Base shear results

[image:4.595.35.310.84.410.2]

6. RESULTS

Table-4: Comparison of base shear results

2.0 2.5 3.0 3.5 4.0 4.5 5.0 1000

1500 2000 2500 3000 3500 4000 4500 5000

1255.92

2045.36

3014.21

4557.19

1283.99

2079.34

3023.92

4637.61

Base

Shea

r (

KN)

Zone

Manual Staad

Fig-10: Zone v/s Base shear

7. CONCLUSION

The above checks can help to a greater extend and it makes sure that the user has modeled the structure with no mistake and further that there is no error in the input. After running the analysis also a simple check on the result can be made using the available formulae.

 Manual analysis results are compared with the STAAD results and identified that the variation is at max 3%.

 The value of base shear in Staad is more than the value of base shear by manual analysis.

 Always better to know two or more than a single software so that a counter check can be made especially for a large and mega projects to avoid suspicious results and to continue his design with peace of mind.

8. REFERENCES

1. IS-875(PART-1) : 1987 Indian Standard CODE OF PRACTICE FOR DESIGN LOADS (OTHER THAN EARTHQUAKE) FOR BUILDINGS AND STRUCTURES Ah Actual weight of

building Lateral load Vb=(Ah*W)

0.127 18512.314 36516.594 4637.607

0.0848 18512.314 35659.394 3023.917

0.0565 18512.314 36802.537 2079.343

0.0353 18512.314 36373.863 1283.997

ZONE MANUAL STAAD PRO

2 1255.92 kN 1283.99 KN

3 2045.36 kN 2079.34 kN

4 3014.21 kN 3023.92 kN

5 4557.19 kN 4637.61 kN

Zone Manual Staad %Increment

2 1255.92 1283.99 2.18

3 2045.36 2079.34 1.63

4 3014.21 3023.92 0.32

[image:4.595.322.559.128.439.2]

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BUILDING MATERIALS AND STORED MATERIALS. 2. IS-875(PART-2): 1987 Indian Standard CODE OF PRACTICE FOR DESIGN LOADS (OTHER THAN EARTHQUAKE) FOR BUILDINGS AND STRUCTURES PART 2 IMPOSED LOADS.

Comparison Between Manual Calculation and Software Calculation of G+5 Building using STAAD